This invention relates to an electric shift apparatus especially suited with a motor vehicle having an automatic transmission.
Motor vehicles since their inception have required some manner of gear change mechanism to satisfy the varying torque and speed requirements encountered during the typical duty cycle of a motor vehicle. For many years these gear change mechanisms were manual in the sense that they required an operator input from the shift lever or the like to effect each desired gear change ratio. More recently, so-called "automatic transmissions" have become popular in which much of the shifting is done without operator input in response to a sensed speed and throttle opening parameters. These automatic transmissions typically include a mode select member on the transmission housing movable between a plurality of selected positions corresponding to a respective plurality of shift modes within the transmission. The mode select member is moved between its several shift positions by a cable or linkage mechanism extending from the mode select member to a suitable gear selector lever located in the passenger compartment of the vehicle. Various proposals have been made in the past to eliminate the mechanical interconnection between the driver operated lever and the mode select member and provide instead an electrical signal generated by a suitable action on the part of the driver and transmitted electrically to some manner of power means arranged to move the mode select member. Electric shift arrangements of this type are shown, for example, in U.S. Pat. Nos. 4,790,204, 4,841,793, 4,817,471, 4,843,901 and 4,922,769, all assigned to the assignee of the present invention. This invention comprises an improvement of the electric shift apparatus of the type disclosed in the above-identified patents and, specifically, relates to an electric shift apparatus in which a removable module is provided to control the operation of the transmission and/or to enable the starter system of the vehicle engine.